Furnace door assembly

ABSTRACT

This invention is addressed to an improved furnace door assembly including a furnace door having inwardly (toward the furnace) extending members substantially outlining the peripheral boundary of the door which, when the door is closed, form a sealing contact with corresponding outwardly extending members affixed to the furnace wall containing the door portal, said sealing surfaces being disposed perpendicular to the furnace wall containing the door portal and therefore substantially unaffected with respect to their fluid tightness by commonly encountered warpage of the door.

iJnite States te Balaz [451 ,Tan.11,1974

1 1 ruRNAcE noon ASSEMBLY [75] Inventor: Joseph 1K. Ballaz, Northbrook,111.

[73] Assignee: Flinn & Draffein Engineering Co., Northbrook, Ill.

[22] Filed: Mar. 6, 1972 [21] Appl. No.: 232,047

[52] U.S. Cl. 1110/173, 432/250 [51] Int. Cl. 1 23111 7/01), F23m 7/02[58] Field of Search 110/173; 49/226, 49/227, 285, 289; 98/115 LH;432/237, 242, 244, 254, 250

[56] References Cited UNITED STATES PATENTS 2,819,694 1/1958 Hartlc232/250 3,160,404 12/1964 Potenzo et a1. 110/173 R 3,172,825 3/1965Maloney 110/173 R 3,262,407 7/1966 Schramn et al..... 110/173 R2,594,188 4/1952 Longenecker 110/173 R 2,254,900 9/1941 Lessmann 110/173R 2,262,363 11/1941 Hoop 110/173 R 2,270,484 1/1942 Wallerius 110/173 R950,983 3/1910 Abbott 110/173 R 871,421 11/1907 Koppers 110/173 cFOREIGN PATENTS OR APPLICATIONS 571,863 9 1945 Great Britain 110/173Primary ExaminerMeyer Perlin Assistant ExaminerPau1 DevinskyAtt0rneyMcDougall, Hersh & Scott ABSTRACT This invention is addressed toan improved furnace door assembly including a furnace door havinginwardly (toward the furnace) extending members substantially outliningthe peripheral boundary of the door which, when the door is closed, forma sealing contact with corresponding outwardly extending members affixedto the furnace wall containing the door portal, said sealing surfacesbeing disposed perpendicular to the furnace wall containing the doorportal and therefore substantially unaffected with respect to theirfluid tightness by commonly encountered warpage of the door.

5 Claims, 6 Drawing Figures FURNACE DOOR ASSEMBLY This invention relatesto a furnace door assembly. and more particularly to a furnace doorassembly capable of providing an improved seal.

It is well known that all furnace doors have a tendency to warp aftereven relatively short periods of use. It is generally recognized thatwarpage of furnace doors may lead to degeneration of the effectivenessof the means commonly employed for sealing the door against undesirableleakage which may permit infiltration of air into the furnace or effluxof hot atmosphere from inside the furnace. Furnace atmosphere leakagethrough the door seal may permit the escape of costly preparedatmosphere employed inside the furnace for beneficial metallurgicalpurposes. Heat carried by the effluent hot gases usually producesgreater warpage of the door, thus adding to the leakage problem.Furthermore, the hot gases escaping through the door seal maydeleteriously affect the seal itself resulting in a rapid and cumulativebreakdown of the sealing members. Effluent prepared atmosphere escapingthrough faulty seals is not only costly but in some instances may exposethe furnace operators to toxic gases such as carbon monoxide.

Various attempts have been made to effect fluid-tight sealing of furnacedoors; such as, the employment of clamps and dogs which are designed tourge the door inward toward the furnace wall and into contact withsealing surfaces affixed to the furnace wall. While such devices havedemonstrated usefulness, usefullness, their effectiveness is oftenadversely affected by unavoidable warpage of the structural framing ofthe between the stationary and moving components of the sealing membersas the door is closed and opened during normal use of the furnace.

Another object of the present invention utilizes the force of gravityacting upon the door to effect compression of the resilient componentsof the sealing members to achieve fluid-tight sealing of the doorwithout resort to auxiliary devices for achieving said compression ofthe resilient components.

These and other objects and advantages of the invention will become moreapparent hereinafter, and, for purposes of illustration, but not oflimitation, an embodiment of the invention is shown in the accompanyingdrawings in which:

FIG. l is a front elevation view of a furnace door assembly embodyingthe features of the present invention in an open position;

FIG. 2 is a view similar to that of FIG. 1 with the furnace door beingin the closed position;

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 1;

FIG. 4 is a sectional view taken along the line 4l4 in FIG. 2;

FIG. 5 is a sectional view taken along the line in FIG. 2; and

FIG. 6 is a sectional view taken along the line 66 in FIG. 2.

The concepts of the present invention reside in a furnace door assemblycomprising a door having inwardly (toward the furnace) extending sealingelements along the lintel (top), sill (bottom), and jambs (sides)thereof which engage corresponding sealing elements affixed to andextending outwardly from the wall of the furnace containing the doorportal whereby the door sealing elements, when the door is in the closedposition, rest upon the sealing elements which are affixed to thefurnace wall. Thereby, sealing surfaces are defined which areperpendicular to the plane of the furnace wall, and the weight of thedoor urges the sealing members of the door toward a more secure sealingrelation with the sealing members affixed to the furnace wall.

Warpage of the door assembly usually causes a relative motion betweenthe door and the furnace wall in a direction which is substantiallytransverse to the furnace wall. Since the sealing surfaces are alsodisposed transverse to the furnace wall, the warpage motion of the doorwill only produce a slight sliding motion between the sealing surfaces.The transverse warpage motion of the door does not, therefore, cause thesealing surfaces to move apart, and the integrity of the door seal isnot impaired.

Referring now to the drawings, there is shown a door assembly embodyingthe features of this invention. As illustrated in FIGS. II to 3, theassembly includes a door 10 having a generally trapezoidal shape whichis mounted on an inclined vertical furnace wall 12 containing a portal14 through which materials can be passed into or out of the furnace.

In the preferred embodiment, the door It is formed by an outer wall 16.It is generally preferred that refractory material and insulation bebuilt onto the face of wall 16 to define an inner face 18 adjacent thefurnace wall. If desired, the door can be formed with a plurality ofreinforcing ribs 2ll to provide increased structural strength.

As can best be seen in FIGS. 2 and 3, door if) is provided with a flange22 extending inwardly along the lintel or top edge of the door having aninner face 24 substantially perpendicular to the plane of the door. Thisflange 22 may, as shown in FIG. 3, be integral with the top wall 26 ofthe door. Door 10 is also provided with a pair of inwardly extendingjambflanges 23 along each jamb side of the door which similarly have innerfaces 30 substantially perpendicular to the plane of the door. Thesejamb flanges 23 may be integral with the jamb side walls 32 of the doorIll).

The door assembly of the present invention also includes trapezoidallyarranged sealing elements corresponding to the trapezoidal configurationof the door 10 and the lintel and jamb flanges 22 and 28, respectively,extending inwardly toward the wall M of the furnace. The sealing elementincludes a substantially horizontal lintel seal 32 in the form of acontinuous ridge member extending across the lintel, having an outersurface 34 (FIGS. 3 and 4) substantially perpendicular to the plane ofthe door and corresponding to face 24 of lintel flange 26. Lintelsealing element 32 can conveniently be supported by lip 36 extendingalong the lintel. Lintel sealing element 32 can be bonded to lip 36 andwall 12 to prevent slippage, if desired.

The sealing element may also include another horizontal sealing member38 extending across the sill which is supported by a sill support 40.Sealing element 38 can be maintained in position by a channel member 42on the leading edge of sill support 40.

The sealing element also includes a pair of inclined jamb sealingelements 44 which are slightly inclined from the vertical and extendalong jambs of the door assembly. These jamb sealing elements 44 defineouter faces 46 which are substantially perpendicular to the plane of thedoor and which correspond to the faces 30 of jamb flanges 28. The jambsealing elements can be conveniently supported by lips 48 extendingoutwardly from the furnace wall 14.

As is evident, lintel sealing element 32, jamb sealing elements 44 andsill sealing elements 38 define a trape zoidal seal which corresponds tothe trapezoidal configuration of door and the lintel and jamb flanges 22and 28, respectively, thereon. Door 10, in the open position as shown inFIGS. 1 and 3 is elevated above opening 14 by suitable means 50. Toclose the door, door 10 is lowered whereby door 10 slides along wall 12until it reaches the closed position where lintel flange 22 rests uponlintel seal 32 and jamb flanges 28 rest upon jamb seals 44 and the sill52 of the door rests upon sealing element 38. Since the furnace wall 12and consequently the sealing elements are inclined with respect to thevertical, the door 10 is urged toward wall 12 by a component of forceperpendicular to the plane of the door which, when vectorially combinedwith supporting forces parallel to the plane of the door, form aresulting force equal to and opposite to the force of gravity actingupon the door.

Door 10 in its closed position is illustrated in FIGS. 2, 4, and 5 ofthe drawing. As can be seen in these figures, the face 24 of lintelflange 22 rests upon the corresponding face 34 of lintel sealing element32 extending across the lintel of the door, and the faces 30 of the jambflanges 28 extending along the jambs of the door rest on thecorresponding faces 46 of jamb sealing elements 44. Thus, since thefaces of the flanges and sealing elements which are in surface contactare substantially perpendicular to the plane of the door, the sealestablished between these faces is likewise substantially perpendicularto the plane of the door. In addition, the weight of the door serves toslightly compress the sealelements to insure a tight seal.

If the door becomes warped, such distortion does not affect thetightness of the seal since the sealing surfaces lying in planesperpendicular to the door permit a sliding cooperation therebetween aswarpage occurs, to maintain the tightness of the seal. A tight seal isstill maintained where the pressure of the gases inside of the furnaceis the highest, that is, along the jambs and particularly along the topor lintel, since the seal established between the flange elements andthe corresponding sealing elements lies in planes perpendicular to theplane of the door.

The concepts of the present invention are not limited to the trapezoidalconfiguration disclosed in the drawings. For instance, the lintel andjambs of the door might usefully follow the general lines of a parabolahaving its directrix parallel to the door sill. Any other configurationwherein the jamb seals slope downward and away from the vertical axis ofthe door which would cause the door-supporting forces, when the door isin the closed position, acting upon the door through the sealingsurfaces, to exert compressional forces upon the resilient components ofthe sealing members, would properly lie within the scope of thisinvention.

An important variant to the basic disclosure of this invention as abovedescribed provides a means for concentrating the compressional forcesacting upon the resilient components of the sealing members in an areasomewhat less than the transverse sealing surface presented by theresilient components to the mating components of the sealing members.This is accomplished by applying a bead or lip to said mating componentsof the sealing members which engage the resilient components of thesealing surface, said bead having a reduced area of contact. Thecompressional forces acting upon the resilient components of the sealingmembers, being concentrated by the said bead into a reduced area ofcontact, therefore more readily produce a compressional dimpling of theresilient components in order to compensate for unavoidableirregularities in the mating surfaces of the sealing members.

An experimental development embodiment of the door assembly disclosed inthis invention has demonstrated remarkably reduced door seal maintenancerequirements and has resulted in a reduction in prepared atmosphereconsumption attributable to door seal leakage approximating fiftypercent of that required in similar furnaces provided with lessefficient door sealing arrangements.

it will be understood that various changes and modifications can be madein the details of construction and use without departing from the spiritof the invention, especially as defined in the following claims.

I claim:

1. A furnace and door assembly in which the furnace has an accessopening in one of its vertically disposed walls and the door is mountedfor movement relative to the furnace wall to open and closed positionswith respect to said opening, means for effecting sealing engagementbetween said door and wall about said opening, when the door is inclosed position, comprising resilient sealing members and correspondingsealing surfaces in sealing engagement one with the other about theopening to seal the opening when the door is in closed position, withthe sealing members fixed to one of the elements including the door andwall with the sealing surfaces fixed to the other of said elements, theresilient sealing members and surfaces extending for a distance from theadjacent surfaces of the wall and door in the direction substantiallyperpendicular to the plane of the wall and door, whereby sealingengagement between the sealing surfaces and sealing members is along aplane perpendicular to the plane of the wall and door for maintainingsealing engagement therebetween notwithstanding warpage of the wall ordoor in a direction perpendicular to the plane of the wall and door,with the resilient sealing members and sealing surfaces diverging in acorresponding member in their side wall portions whereby the resilientsealing members and sealing surfaces are urged into sealing engagementin response to gravitational force.

2. A furnace and door assembly as claimed in claim 1 in which thesealing members and sealing surfaces are provided in the furnace walland door in a trapezoidal configuration about the wall opening.

3. A furnace and door assembly as claimed in claim 1 in which theresilient sealing members are fixed to the furnace wall about saidopening and extend from the door with the sealing portions to be engagedby the sealing surface facing in the downwardly direction in position tobe engaged by the upwardly facing sealing surfaces on the wall.

5. A furnace and door assembly as claimed in claim 1 in which thefurnace wall containing the opening is inclined from the lintel to thesill in the direction away from the interior of the furnace.

1. A furnace and door assembly in which the furnace has an accessopening in one of its vertically disposed walls and the door is mountedfor movement relative to the furnace wall to open and closed positionswith respect to said opening, means for effecting sealing engagementbetween said door and wall about said opening, when the door is inclosed position, comprising resilient sealing members and correspondingsealing surfaces in sealing engagement one with the other about theopening to seal the opening when the door is in closed position, withthe sealing members fixed to one of the elements including the door andwall with the sealing surfaces fixed to the other of said elements, theresilient sealing members and surfaces extending for a distance from theadjacent surfaces of the wall and door in the direction substantiallyperpendicular to the plane of the wall and door, whereby sealingengagement between the sealing surfaces and sealing members is along aplane perpendicular to the plane of the wall and door for maintainingsealing engagement therebetween notwithstanding warpage of the wall ordoor in a direction perpendicular to the plane of the wall and door,with the resilient sealing members and sealing surfaces diverging in acorresponding member in their side wall portions whereby the resilientsealing members and sealing surfaces are urged into sealing engagementin response to gravitational force.
 2. A furnace and door assembly asclaimed in claim 1 in which the sealing members and sealing surfaces areprovided in the furnace wall and door in a trapezoidal configurationabout the wall opening.
 3. A furnace and door assembly as claimed inclaim 1 in which the resilient sealing members are fixed to the furnacewall about said opening and extend from the furnace wall in a directionsubstantially perpendicular to the plane of the furnace wall with thesealing portions to be engaged by the sealing surface facing in theupwardly direction in position to be engaged by the downwardly facingsealing surfaces on the door.
 4. A furnace and door assembly as claimedin claim 1 in which the resilient sealing members are fixed to the innersurfaces of the door to extend therefrom in a direction substantiallyperpendicular to the plane of the door with the sealing portions to beengaged by the sealing surface facing in the downwardly direction inposition to be engaged by the upwardly facing sealing surfaces on thewall.
 5. A furnace and door assembly as claimed in claim 1 in which thefurnace wall containing the opening is inclined from the lintel to thesill in the direction away from the interior of the furnace.